I always thought the primary purpose of a strut was to ease the load on the guy by providing a wider-angle. I remember needing two-hands on a primary winch to trim a guy close-reaching in a breeze without a strut on even a C&C 33 - put the strut up and it was much more manageable.
I think the use of of tweaker blocks allowing trimming the guy to the rail amidship spelt the end of strut use on most boats by providing similar leverage without the extra hardware or running around...